Reason for imprinting

The reason for imprinting is unknown. Sam Uley believes that a shape-shifter imprints on the person with whom he has the best chance to reproduce. How this applies to Jacob Black and Renesmee is debatable. Part of the reason may be because of how many chromosomes they have, both Renesmee and Jacob have 24 pairs, making it possible for them to have a child at some point when Renesmee matures. Billy Black, however, thinks that imprinting is designed to make the shape-shifter stronger. While never stated directly, Billy's theory may explain Jacob's imprinting on Renesmee; she may provide him with greater support, or if they can reproduce, some vampiric traits (such as hardened skin, perfect memory, or a supernatural gifts) may be transferred to shape-shifters, reducing their weaknesses in human form.